Cost Protecting graphics with liquid laminates can cost as little as two or three cents per square foot on applications such as short-term displays and as much as 30 to 38 cents per square foot—or more—on demanding, long-term applications such as digitally printed wallcoverings. System price largely depends on the type of liquid laminator. UV systems are typically more costly up front than those that apply water-based coatings, because they use UV-curing lamps and are configured to process printed substrates very quickly. In some cases, a UV coater may be just slightly less expensive than a water-based system five times its width.

Liquid types UV coatings for printed graphics are made without the use of VOCs. They’re composed entirely of convertible solids, meaning they become plastic with nothing evaporating in the process. Water-based coatings, which are often composed of 70% water and 30% resins, take longer to set because the water content must be allowed to evaporate completely before the substrates can be rolled or stacked. Flexible displays benefit from solvent coatings, which are designed to resist becoming brittle or cracking with age.

It’s no secret that exposure to ultraviolet light cures UV inks and coatings, but it’s that property that prevents UV-curable liquid laminates from offering graphics protection from sun damage. Any sort of UV inhibitor would prevent the coatings from curing. Therefore, the primary purpose of UV liquid laminates is to shield printed graphics from scratching and abrasion.

Those who print solvent or eco-solvent inks should use water-based liquid laminates. In general, when selecting a liquid type, reverse the coating—for example, use a water-based coating on a solvent inkjet print, and vice versa.

Water-based liquid laminates, like aqueous screen-printing inks, do contain some solvents. The VOC content of these coatings has dropped over the past few years—even in products designed for stain and graffiti resistance; however, you should make sure to keep an MSDS on for each water-based coating you use.

Solvent liquid laminates are most often applied to water-based prints. They may be formulated with components that absorb UV light, as well as stabilizers that inhibit polymer degradation caused by photo-oxidation or thermal exposure. Solvent coatings also may contain leveling agents, which promote smoothness in a coating’s surface.

Speed Some UV liquid laminators, for example, are able to cure at high speeds, sometimes at more than 100 ft/min. As such, they may be designed with very conservative footprints. For example, the total length of such a machine may be less than 5 ft, including the conveyor, because the machine is able to process a lot of media quickly.